1. Technical Field
This invention relates to a lignin sorbent, a lignin removal unit, a lignocellulosic biorefinery, a process for removing lignin, a process for binding lignin, and a renewable material.
2. Discussion of Related Art
Tightening oil supplies and escalating energy prices along with environmental concerns over nonrenewable resources have prompted significant interest and research into renewable materials and/or biofuels. Efforts to reduce carbon emissions and greenhouse gases are also driving investment into renewable materials and/or biofuels.
One area of cost for production of renewable materials is hydrolytic enzymes. Stephanopoulos, Challenges in Engineering Microbes for Biofuels Production, states “[d]espite substantial reduction in the cost of cellulolytic enzymes [ ], sugar release from biomass still remains an expensive and slow step, perhaps the most critical in the overall process.”
Himmel et al, Biomass Recalcitrance: Engineering Plants and Enzymes for Biofuels Production, states the “cost-competitive production of biofuels is currently prevented by the high cost of biomass feedstocks and the processes for converting biomass to sugars—that is, the cost of the thermochemical pretreatment and enzyme hydrolysis unit operations in a biorefinery.”
Sticklen, Plant genetic engineering to improve biomass characteristics for biofuels, states the “idea that fermentable sugars for use in the production of alcohol fuels could be derived from crop biomass has been well received by the US Federal government; however, major economical downsides of biomass refineries include the pretreatment processing of the lignocellulosic matter and the cost of production of the microbial cellulases needed to convert the cellulose of biomass into fermentable sugars.”
Aden et al., Lignocellulosic Biomass to Ethanol Process Design and Economics Utilizing Co-current Dilute Acid Prehydrolysis and Enzymatic Hydrolysis for Corn Stover, published by the National Renewable Energy Laboratory discloses an ethanol plant process design using corn stover for a feedstock. The entire teachings of Aden et al. are hereby incorporated by reference in their entirety.
However, even with the above improvements in the processes, there is a need and a desire to reduce usage enzyme costs and produce renewable materials in a more cost effective manner.